BOx build with detailed picture

im trying to build a box for my 1991 hatchback 5.0l and need some help!
im putting in a W12GTi 12, and want the box to be around 2.25 cubic feet tuned to 30 hertz, after the displacement of the ports and sub, specs of the trunk are

Hieght: 20" at front then 15" in middle and then 12" at the rear goes down because of hatch!
width:36" at front and 45" at rear
lenght:30"

heres the type of designs i was thinking and im using 3/4 mdf and im gonan double it up on the front! so im asking if anyone can help me with the dimensions and what ports to use, thanks you, jeremy